In restorative and preventive dentistry, filling cavities, dental defects or root canals of teeth is of special importance. Apart from a plurality of different materials (e.g. gutta-percha, amalgam, gold), composites are also used as filling materials. Composites are mixtures of a polymerizable plastic matrix with organic and inorganic filling materials. The polymerization of these composites is triggered by exposure to visible blue or ultraviolet light after the composites have been applied into the cavity. Thus, the method which is currently common is comprised of first applying the composite into the cavity and subsequently hardening the composite by exposure to light.
All composites tend to form gaps due to their shrinkage behavior during hardening such that in case of the formation of a gap the tooth cavity will not be hermetically sealed. Due to this lack of hermetic sealing of the tooth cavity bacterial infestation of the gaps is possible and thus new caries and pain can be caused.